The Financial Services Compensation Scheme has declared investment management firm Independent Portfolio Managers in default.
IPM provided private portfolio management services and managed a range of specialist funds for its clients, including mini-bonds.
The news comes after a long-running dispute between IPM and its customers, which saw investors lose millions from the failure of two mini bonds the firm had promoted.
The FSCS said many of these customers still had outstanding complaints with IPM and the Financial Ombudsman Service.
Jimmy Barber, chief operating officer at the FSCS, said: "We estimate that 2,000 UK customers may be affected by the failure of IPM. However, the value of potential negligence claims is still unknown.
"We encourage all former IPM customers who think they might be entitled to compensation to make a claim on our website right away."
Since June the Fos has ruled on three cases involving IPM and bonds issued by Secured Energy Bonds Plc, which has now gone into administration, though the invitation document was approved by IPM.
Upholding one of the complaints, ombudsman Philip Roberts said the invitation document should not have been approved because it was unfair, unclear and misleading.
One of the problems the ombudsman found was that CBD Energy, an Australian company which owned and operated solar and wind farms and which was a subsidiary of Secured Energy Bonds, was not in a strong enough financial position to be able to repay bondholders on demand if called to do so under the guarantee it gave.